Polycyclic aromatic hydrocarbons as a geochemical markers for oil pollution of the environment

Justify the role of polycyclic aromatic hydrocarbons (PAH) as a geochemical marker of the environment pollution. Considered the possibilities of use of the indicator ratios based on the PAHs’ concentrations in the environmental and technogenic objects for the identification of the genesis of the pollution. On the example of 24 cases (crude oil from different regions of the world, oil slimes and oil reservoir sediments) estimated theefficiency of different diagnostic ratios and their adequacy for the conditions of Russia. Shown the possibility of identification of the genesis of oil pollution using multivariate statistical methods.
Materials and methods
1. Published information about composition of oils and oil containing wastes (concentrations of Polycyclic aromatic hydrocarbons, PAH) in different regions of Russia, USA, North sea at al. 2. Calculation of the indicator ratios for the identification of genesis of PAH (petrogenic or pyrogenic) and their source. 3. Analyses of the informativity of indicator ratios of PAH (Accuracy of the classification of samples according to the source of origin). 4. Statistical methods, including correlation and component analysis.
Results
The optimal indicator ratios for the identification of oil genesis of the pollution of environment and technogenic objects are justified. Received the conclusions about the possibility of use of the transit pointsof the indicator ratios of PAHs, established in the foreign studies, for the natural and technogenic objects in Russia. The role of the natural factors in the restructuring of the PAH ratios as a part of oil pollutionsis assessed. It allows to consider the age of the pollutions at the analyses of the indicator ratios.
Сonclusions
1. Use of the indicator ratios of PAHs allows to identify the genesis of PAHs in oilsand oil slimes with the different levelof reliability. Maximum accuracy in thedivision of the pyrogenic and petrogenicPAHs achieves using the indicator ratio Fl/ (Fl + Ру) - PAH with the molecularmass 202.2. Wide used in the foreign researches“transition points” of the indicator ratioscan not be automatically translated forall the conditions of the environmentand all components of the environment. The significant correction of their use is necessary depending on studied materials and the period of their storage. It is necessary to duplicate the physical-chemical analyses as well as ways and methods of extraction of PAHs. 3. Application of the complex of coefficients-indicators of PAHs genesis allowsto more sure divide the oil containingsamples of the different nature,composition and “age” (time of thecontact with the terms of the earth'ssurface). 4. Conditions of the environment (ofthe earth surface) make a significanteffect on the composition and relationof PAHs. Transformation of the oilproducts on the earth surface andtheir migration in the componentsof the environment leads to therestructuring of the ratios of the PAHin their compared with the initial“fresh” oils and pollutions. This isreflected in the values of the indicatorratios. Thus, there is the possibility ofthe identification of oil pollutions ofdifferent "ages".